Marine Interpretation Message
Issued by NWS

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000
AGPN40 KWNM 271414
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
714 AM PDT WED AUG 27 2014

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.

AS A WEAK COLD FRONT APRCHS THE PZ5 WTRS THE HIGH PRES RIDGE W OF
THE OFSHR WTRS HAS WEAKENED WHICH HAS ALLOWED THE NNWLY GRADIENT
ACRS THE OFSHR/CSTL WTRS TO HV WEAKENED SO THAT MAX WINDS ARE GNLY
15-20 KT...OR LESS...THROUGHOUT. AS HURCN MARIE PASSES WELL S OF
THE AREA IT CONTS TO SEND LONG PERIOD SLY SWELL NWD INTO THE
SRN/CNTRL PZ6 WTRS WHR MAX SEAS ARE IN THE 9-12 FT RANGE WHICH ARE
BEING HANDLED SLIGHTLY BETTER BY THE 06Z ENP AND ENPH VERSIONS OF
THE WAVEWATCH III VS THE 00Z ECMWF WAM MDL.

OVER THE SHORT TERM...THE LATEST MDLS PRESENT NO SIG FCST
PROBLEMS. THE MDLS ARE IN GOOD AGRMT THAT THE WEAK COLD FRONT WL
DRIFT SE INTO THE PZ5 WTRS LATE TODAY INTO THU WHL GRADLY WASHING
OUT. THE END RESULT OF THIS FROPA WL BE TO KEEP THE NNWLY GRADIENT
OFSHR REL WEAK WITH LITTLE CHNG IN STRENGTH THRU THU NITE. SO DO
NOT PLAN ON REPOPULATING THE PREVLY USED 00Z GFS 10M BL WINDS AND
WL JUST MAKE SM MINOR INSIG SHORT TERM TWEAKS TO THE PREV OFSHR
FCSTS.

IN THE LONG RANGE...TO VARYING DEGREES THE LATEST GLOBAL MDLS ALL
FCST A SERIES OF WEAK FRONTS AND/OR SFC TROFS TO PASS ACRS THE PZ5
WTRS FRI THRU SUN MAINTAINING GNRLY WEAK GRADIENTS ACRS THE PZ5
WTRS. BY LATE SAT INTO SUN NITE THE GLOBAL MDLS ALL FCST A HIGH
PRES CENTER TO REBUILD SLOWLY EWD TWDS THE PZ5 WTRS WHL COMBINING
WITH A GRADLY STRENGTHENING INLAND LOW PRES TROF ACRS CA TO CAUSE
A GRADLY STRENGTHENING NNWLY GRADIENT TO DVLP ACRS MUCH OF THE PZ6
AND SE MOST PZ5 WTRS. FOR NOW WL CONT TO FAVOR THE SLIGHTLY MR
CONSERVATIVE 00Z ECMWF SOLUTION FOR THIS STRENGTHENING GRADIENT.
SO PLAN ON MAKING NO MAJOR LONG RANGE CHNGS IN THE NEXT OFSHR FCST
PACKAGE.


-----------------------------------------------------------------
PREVIOUS DISCUSSION...

THE MAIN CONCERN OVR THE NEXT DAY OR TWO WILL CONTINUE TO BE THE
LONG PERIOD S SWELLS ASSOC WITH HURCN MARIE CURRENTLY LOCATED
ABOUT 450 NM S AND SW OF THE SRN MOST SOCAL OFF WTRS. PER THE
LATEST NHC ADV...MARIE IS FCST TO WEAKEN TO A TROPICAL STORM LTR
TDA...AND THEN BECOME POST-TROPICAL NR 26.5N 130.3W BY 48 HRS OR
AT 00UTC AUG 29TH. FOR ADTL INFO PLS REFER TO THE LATEST ADV FROM
THE NHC. OTW...THE REGION WILL REMAIN BETWEEN HIGH PRES W OF THE
WTRS...AND A LOW PRES TROF INLAND OVR THE WRN STATES TDA THRU
TNGT. A WEAK COLD FRONT WILL APPROACH PZ5 WTRS FROM THE NW LTR
TDA...AND THEN CROSS THE WTRS AS IT DSIPTS TNGT INTO EARLY THU.
HIGH PRES WILL BUILD TO THE W OF THE WTRS BEHIND THE FRONT LTR
THU INTO FRI. ANOTHER WK COLD FRONT WILL CROSS THE PZ5 WTRS LTR
FRI INTO FRI NGT...AND THEN DSIPT BY SAT. A THIRD WEAK COLD FRONT
WILL REACH THE PZ5 WTRS LTR SUN OR SUN NGT. ELSEWHERE THE
INTERACTION BETWEEN HIGH PRES W OF THE WTRS...AND LOW PRES NR THE
COAST AND INLAND WILL CONT THRU THE WK INTO THE WKND...WITH SOME
INCREASE IN N-NW WINDS LKLY OVR MAINLY CALIF OFF WTRS BY THE WKND
AS THE PRES GRAD BETWEEN THESE TWO SYSTEMS BEGINS TO STRENGTHEN.
OVRALL...NO MAJOR CHANGES FROM THE PREV FEW OPC FCSTS FOR THE
EARLY AM PACKAGE.

MODELS...THE 00Z MDLS REMAIN IN VRY GUD AGREEMENT OVR THE OFF
WTRS THRU SAT NGT. AS A RESULT...WE WILL STAY CLOSE TO THE 00Z
GFS 10M WINDS FOR THE OFF WTRS FCST INTO SAT NGT. FOR SUN AND SUN
NGT THE 00Z GFS IS A LITTLE STRONGER VS THE REMAINING NON-GFS
GUID REGARDING A COLD FRONT REACHING THE PZ5 WTRS. WE WILL
THEREFORE TREND THE FCST MORE TOWARD THE 00Z ECMWF MDL FOR SUN AND
SUN NGT WHICH ALSO FITS CLOSER TO THE NEW MED RANGE GUID FROM WPC.

.SEAS...LONG PD S SWELLS GENERATED BY HURCN MARIE ARE STILL FCST
TO PERSIST OVR THE OFF WTRS TDA INTO TNGT...AND THEN DECAY LTR
TNGT THRU THU AS MARIE WEAKENS AND TRACKS FURTHER TO THE W AND NW
AWAY FROM THE WTRS. OVRALL...THE 00Z ENP WW3 MDL GUID IS RUNNING
SLIGHTLY HIGHER THAN THE OBS AND ALTIMETER PASS DATA NOTED OVR
THE OFF WTRS PER THE 06Z RP1 SEA STATE ANALYSIS. IT IS HOWEVER
CLOSER THAN THE 00Z ECMWF WAM WV GUID WHICH IS RUNNING UP TO 4 TO
5 FT ON THE LOW SIDE OFF THE SOCAL COAST. WE WILL THEREFORE
REMAIN CLOSE TO THE ENP WW3 MDL OUTPUT THRU SAT NGT...AND THEN
TRANSITION TO THE ECMWF WAM WV GUID THEREAFTER AS WE ALSO TREND
FROM THE GFS TO THE ECMWF FOR WINDS AS NOTED ABV.

.EXTRATROPICAL STORM SURGE GUIDANCE...NA


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER VUKITS/MILLS. OCEAN PREDICTION CENTER.


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